Developement and operation of an electro-optical gravitational waves detector simulator as part of the space mission elisa/ngo

Transcription

1 gravitational space mission PhD student : Pierre Gruning Thesis director : Hubert Halloin

2 Contents gravitational

3 Contents gravitational

4 Contents gravitational

5 Contents gravitational

6 Plan gravitational

7 gravitational Perturbation of the space-time metric induced by acceleration of masses Main sources are binary systems of black holes, neutron stars, white dwarfs, stochastic background, non-symetrical neutron stars Predicted in 1918 by Einstein Never directly detected but undirectly observed by Russell Hulse and Joseph Taylor (Physics Nobel Prize 1993) by observations of the binary pulsar PSR B

8 R µν 1 2 g µν R + Λ g µν = 8πG c 4 T µν R µν being the Ricci tensor, g µν the metric tensor, T µν the impulse-energy tensor and R the scalar curvature. gravitational After linearisation and in the case of weak field using g µν = ν µν + h µν, ν µν being the Minkowski metric and h µν the perturbation from GW, we get the wave equation : h µν = 16πG c 4 T µν

9 Plan gravitational

10 (evolved Laser gravitational from LISA to elisa : redefining the mission mission concept selected by ESA for L3 with estimated launch in 2034 launch of LISA Pathfinder in 2014

11 (evolved Laser gravitational I I 3 satellites, 2 arms forming a giant heterodyne michelson interferometer 1 million km arms allowing to be sensitive to variations of picometer order induced by gravitational I satellites contains test masses (75% gold, 25% platinum, 2,5cm x 2,5cm) islotated from perturbations and following geodesics

12 (evolved Laser The goal of elisa is to detect gravitational deformations as small as L/L Hz (i.e 10 pm per million of km) around 5 mhz requiring a perfect knowing of noise sources such as : laser noise shot noise radiative pressure from the sun cosmic rays charging the test masses optical path lenght variation due to thermodynamical effects acceleration of the test masses and optical bench noise of the clocks uncertainty on the laser pointing noise due to diffuse light in the optical bench and many other effects... gravitational

13 Plan gravitational

14 , an simulator of elisa, optical part gravitational I I I a heterodyne Mach-Zehnder interferometer 2 blocs each one representing a satellite and 3 arms each arm simulated by an association of lense, polarizing plate, mirror and acousto-optical modulator

15 , an simulator of elisa, electronical part GPS disciplined oscillator 5 MHz max Synth. 10 MHz NI PXIe 6537 Interface board gravitational Phasemeter MHz x8 PD #1 PD #2 1 GHz Direct digital synthesizers DDS #1 DDS #2 DDS #3 Ref Channel #1 Signal Ref Channel #2 Signal Ref Channel #3 Signal Ref Channel #4 Signal AOM #3 AOM #2 AOM #1

16 gravitational X 1 st = (1 D 31 D 1 3)s TT ;1 (1 D 2 1D 1 2)s TT ;1 a post-measurement treatment to reduce significantly the noise level

17 Improvement of the isolation of the optical bench use of air cushion heat device to reduce turbulences by creating temperature layers further improvements for the future : transfer into a vacuum chamber piezo oscillators on the mirror for active correction of the optical path lenght replacement of the NI device by a FPGA card gravitational

18 Some results LTPDA 2.7 (R2013b) :26: UTC ltpda: f3f3872 iplot ASD (Hz/sqrt(Hz)) LASD(freq chan 1) LASD(freq chan 2) LASD(freq chan 3) LASD(freq chan 4) LASD(TDI_f34) Frequency [Hz] gravitational

19 Some results LTPDA 2.7 (R2013b) :35: UTC ltpda: f3f3872 iplot 10 2 gravitational ASD (Hz/sqrt(Hz)) LASD(freq chan 1) LASD(freq chan 2) LASD(freq chan 3) LASD(freq chan 4) LASD(TDI_f12) LASD(TDI_f34) Frequency [Hz]

20 Some results LTPDA 2.7 (R2013b) :34: UTC ltpda: f3f3872 iplot [Hz 1/2 ] LASD(TDI_f34),retards 6.5 et 6.7 LASD(TDI_f34),retards égaux 6.5 LASD(TDI_f34),aucun bruit LASD(TDI_f34),retards et Frequency [Hz] gravitational

21 Plan gravitational

22 very complete simulator, both for optical and electronical uses and soon for applications of an informatical simulator test bench for noise reduction procedures such as TDI, arm-locking and also for device tests like phasemeter prototype "Progress towards an simulator for space based, long arms interferometers" gravitational